1. Field of the Invention
The present invention relates generally to the field a data communications between infrared (IR) devices, and more particularly to data communication between a handheld computer having an optical interface port that transmits and receives signals with an optical interface port of an automatically activated fluid dispensing device.
2. Technical Background
Standard IR devices communicate in accordance with the Infrared Data Association Serial Infrared Physical Layer Specification (hereinafter referred to as the Serial Infrared Specification) promulgated by the Infrared Data Association (IrDA). The IrDA is a standard body that publishes specifications containing the criteria by which IR device manufacturers must comply in order to claim IrDA compliance. The Infrared Data Association Serial Infrared Specification is incorporated herein by reference.
The physical layer specification governs point-to-point communication between electronic devices, such as computers and peripherals, using directed half-duplex, serial infrared communication links through free space. The physical elements, including the optical links and active input and output interfaces, are described in the physical layer specification. In order for a device to be IrDA compliant, the device must be designed to meet the specifications as indicated in the physical layer specification.
In particular, the IrDA Physical Layer Specification places constraints on the communication procedure when a device attempts to establish an optical link with a second device. The IrDA Physical Layer Specification sets forth requirements that govern the behavior of a device having a transmitter/detector pair when establishing an optical link. Compliance with the IrDA Physical Layer Specification requires that the device sample its detection range. An IrDA compliant device will not transmit a pulse to another device to request a link until it detects 500 msecs of “media quiet.” “Media quiet” means that there is no IR activity detected during the 500 msecs duration.
Once an optical link is established between two devices, IrDA compliance requires that a serial interaction pulse (SIP) be emitted every 500 msecs to quiet other potentially interfering systems. In other words, the 500 msecs “media quiet” requirement will ensure that the potentially interfering device detects an SIP every 500 msecs thereby precluding the device from attempting to establish a connection.
The SIP is required by the Physical Layer Specification to quiet slower systems that might interfere with the optical link established between the transmitter and the receiver. An SIP is a 1.6 microsecond pulse followed by a 7.1 microsecond off time of the transmitter. The SIP simulates a start pulse that requires a potentially interfering system to listen for at least 500 milliseconds prior to establishing an optical link.
In accordance with the Physical Layer Specification, optical sensors are commonly employed with IR transmitters which, together with processing electronics, are used to detect an object in the range of the IR transmitter. An IR pulse is emitted, and if it strikes an object in its range, the pulse is reflected. An IR sensor is placed strategically in order to detect the reflected pulse.
The dichotomous emitter/sensor technology is employed in various applications including automatically activated fluid dispensing devices. Such dispensing systems, such as hand activated water faucets, generally include an infrared emitter that emits a timed pulse. When an object, such as a user's hands, is within the emitter's range, it reflects the pulsed IR beam, and the optical sensor detects the reflected light from the user's hands. In such a system, an IrDA compliant device emits a pulse every 250 milliseconds.
Automatically activated fluid dispensing devices have a myriad of operating pitfalls. For example, devices such as IR controlled faucets require extensive manual servicing and maintenance. Inherently, in an environment such as an office building having numerous floors and numerous faucets in each of the restrooms on each of the floors, servicing and maintenance of the IR controlled devices is often a burdensome and time consuming task. Many simple tasks associated with the maintenance of the faucets, including battery replacement, IR range monitoring, and solenoid malfunction detection, are typically performed per faucet per restroom per floor in an office building. This type of monitoring of malfunctioning units dictates manual interaction with each unit for diagnostics, maintenance, calibration, and servicing.